


Challenging Assumptions

by TrinityEverett



Category: Castle
Genre: Alternate Universe, F/M, Prompt Response, season 3 fic
Language: English
Status: Completed
Published: 2020-05-30
Updated: 2020-05-30
Packaged: 2021-03-03 02:13:45
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,095
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24447145
Author URL: https://archiveofourown.org/users/TrinityEverett/pseuds/TrinityEverett
Summary: "Maybe it's her own fault for making assumptions, but she'd been anticipating someone a little shorter, someone a little greener, and, well, someone male." - A Season 3 AU, Caskett.
Relationships: Kate Beckett/Richard Castle
Kudos: 17





	Challenging Assumptions

**Challenging Assumptions**

**A Season 3 AU**

**_Prompt from monalyssa33: What if Castle's protege (Alex Conrad) was actually a beautiful woman? How does Kate react to that?_ **

* * *

Alex Conrad is… not what she'd expected when Castle had approached her about allowing his mentee to stop by the precinct for a little while. Maybe it's her own fault for making assumptions, but she'd been anticipating someone a little shorter, someone a little greener, and, well, someone male. Instead, she finds herself shaking hands with a dark-haired, keen-eyed woman who's just about her height. She's well-dressed, wearing a blouse and skirt that Kate herself had tried on and loved, but had dismissed because of the exorbitant price tag. Altogether, she's left Beckett floundering a bit.

 _This_ is Alex Conrad, Castle's protégé?

"You look surprised, Detective Beckett," Alex says, kind though her lips lift. Oh, Kate's shock amuses her. "Were you expecting someone else?"

"I, ah, no. No. Castle told me you would be coming by today. I just thought you would be meeting him."

"Oh, I am, I'm just early and I thought I would introduce myself. But if you're busy, I can wait somewhere else."

"No, no, I was just focused on… you know what, don't worry about it. It's nice to meet you."

Conrad smiles again, wider this time. "You as well. I've ready _Heat Wave_ and _Naked Heat_ so many times, I feel like I know you. Not to mention the fact that Mr. Castle has told me so much about you."

Well, that makes one of them who knew what to expect. Beckett forces her smile to widen, hoping it doesn't look pained or fake.

"Why don't I show you around a little?" she offers, already locking her computer and closing the open files on her desk. "And I can answer any questions you might have? Castle said you're working on a new book?"

"That would be great." Conrad nods, falling beside Beckett, matching her – maybe a tad brisk – steps easily. "I am. Mr. Castle has been an amazing help. And he's an amazing resource and a great mentor, don't get me wrong-"

Beckett tries not to snort. Yeah, she'll bet he is.

As soon as the thought crosses her mind, it passes. That's not fair to Castle. He's good at his job, good enough to be a role model to someone, even if that someone is–

"-but I wouldn't mind seeing how the real police do things," Conrad finishes, oblivious to Kate's growing internal tug of war.

"Understandable," she says, picking up the thread. "After all, you also have to take what Castle says with a grain of salt. Maybe an entire can of salt."

Alex laughs, shaking her head. "You don't have to tell me that. The first time I spoke to him, he almost had me convinced that he had actually been given a badge and an official position."

This time she does snort. "No. He's helpful, but that's not something we do here. Unless you're seven. And he is not seven years old, no matter how much he acts like it."

Conrad grins, a little bit sly. "Oh no, he's not."

Beckett's eyes cut to her, considering the statement – doing her best not to bristle at the implication; her partner is a grown man and can do whatever he wants with whomever he wants – before deciding to let it go. If Conrad catches on, she doesn't show it. Instead, she's all smiles and awed looks around the room.

"So, as you saw, the detectives who work on this floor have their desks here. It makes for a more collaborative environment. We're able to work as a team, toss ideas around, etc. Unis have a space down the hall as well where they can take care of their paperwork after each patrol." She nods to a few of the officers milling around, lifting an eyebrow at their quizzical looks.

Two plus years with Castle around and they're still surprised when his antics spill over; one would think they'd be used to this kind of thing by now.

"Don't mind them," she says looking at Conrad. "It's a slow day."

Alex laughs. "But you have a case, right? The one you were working when I walked up, the swimmer kid?"

Beckett tilts her head, impressed. "Observant."

Conrad lifts a shoulder. "Writer's habit."

"Yeah, I've heard that before, but you're right. We are working that case. We're kind of at an impasse right now, though."

"Well maybe you're looking at it wrong?" Conrad offers. "Maybe the steroids have nothing to do with his murder. Maybe they're your red herring."

Beckett stops, stepping out of the walkway and turning to face her. "What do you mean?"

Alex shifts. "I was, well, I was just looking at the board before I introduced myself and I noticed that this swimmer kid, he's caught between two worlds. Now, if I were writing the story, the steroids would just be a red herring and the real killer would be someone from the old neighborhood." She rubs her hands together. "But… you would know better than I do. I'm new at this, after all."

"No," she assures. "No, that's a good point. We've just been assuming up to this point, we don't have proof that this has anything to do with the steroids. We do need to look into his past."

Conrad brightens. "Really? That was helpful?"

"It was. And it is nice to get that outside perspective sometimes," Beckett assures as some of her reticence slips away.

"Since when?" Her partner asks from behind them. They turn, finding Castle looking between them with wary eyes.

"Since the suggestions didn't include conspiracies or alien intervention," Beckett quips. "I was just showing _Alex_ around, Castle."

Her quiet emphasis and quirked eyebrow hits home and her partner chuckles. "I'm sorry, I meant to be here sooner to introduce you to one another. Alex, good to see you again. I'm glad you and Beckett were able to talk."

The other woman tilts her head. "Good to see you, Mr. Castle."

"Rick, please."

Conrad nods. "Rick. And I'm sorry if I overstepped, I just got here early and thought why not head up?"

Castle waves her off with an easy smile. "No, no. No overstepping. I'm glad you've met."

"Oh, good," Conrad exhales, laughing quietly. "I can't tell you how much I appreciate you setting this up, Rick. I'm grateful for the chance to look around and talk to everyone, really get some authenticity for my next book."

Castle's smile deepens. "Of course. So, what were you guys talking about?" he asks, looking in Beckett's direction again. "Talking about me? How ruggedly handsome I am?"

"Oh yeah," she drawls. "We were just taking a lazy walk, talking about how dreamy you are. Your eyes, and your hair, and your–"

"Okay, okay, I get it."

Her tongue pokes between her teeth before she shelves the mischief and brings him up to speed. "I was giving Alex a tour of the floor and she asked me about our case. She suggested that the steroids aren't where we should be focusing our efforts, but on Zack's old neighborhood."

Castle turns. "Interesting thought. Feels pretty good, doesn't it?"

Alex grins, bouncing on her feet. "It feels amazing. I can see why you like doing this, Rick. And I know you probably have to go back to work soon, Detective, so I'm sure Rick can show me around the rest of the way," she pauses, tearing her eyes from Castle's face to look at Beckett. "But maybe later we can chat some more? If you have time?"

Beckett nods. That's assuming Conrad and Castle don't make other plans. "Of course. I'll be happy to answer any other questions you have. Here, let me get you my card and you can give me a call."

She moves to her desk and back, finding her partner standing with the other woman, already deep in a story she only barely gets the gist of; something about Ryan and Esposito and yet another one of their juvenile bets. Conrad looks away from Castle's antics just long enough to take her card and thank her again.

"It was really good to meet you, Detective."

"You too, Alex. Have uh, have a good visit, and don't let him get you into too much trouble."

She glances at her partner, watching his mouth open and close a couple of times. "I'll let you know if anything comes up, Castle."

He joins her at her desk just after she makes it back, practically scuffing his foot over the hardwood like a kid waiting for a punishment.

"So uh, this is okay with you, right? Me showing Alex around."

Beckett looks up from the unopened file in her hand. "What? Sure, yeah. Why wouldn't it be?"

"Well… we do have a case."

"Us catching a case didn't exactly faze you before, Castle. If it'd been a problem to have her here while we have an open case, I would've said so earlier and I would've told you to reschedule."

He nods, eyeing her dubiously. Beckett rolls her eyes in return, lifting her chin. "Are _you_ okay with showing her around?"

"Am I?" He blinks. "Of course I am. I just… wanted to make sure you were fine with it."

"I'm fine with it," she says, dry. She doesn't really have the option _not_ to be fine with it, and she's certainly not going to tell him she's still put off by his lack of candor regarding his mentee.

"And you are," he says, clapping his hands. "Great."

"Great," she repeats, flipping open the file when Castle practically jogs back to Alex Conrad's side.

* * *

"Okay, what is eating you?" Lanie asks over the carton of takeout Kate had shoved her way a few minutes earlier. "You never bring me dinner."

"That's not true," she denies, though she's hard-pressed to think of the last time she _had_ brought food for Lanie while her friend works a double shift. "I… it's just been a while."

Lanie takes a bite of the tofu fried rice she'd brought her. "Uh huh. And I'm sure your visit and your general, this," she waves her hand in Kate's direction, "has nothing to do with the rumor that Castle's protégé is not the Alex Conrad you were expecting them to be."

Beckett narrows her eyes. "What have you heard?"

"Uh huh. That's what I thought. So…"

"So, nothing. Alex Conrad is a perfectly nice person and me being here has nothing to do with that."

"And the fact that Castle's with her?" Lanie offers, smirking behind her fork. "Does that have anything to do with why you're here tonight?"

"He's helping her. She's his mentee, as he says. He helped her get her break and now he's helping her work on her next book. It's not a big deal."

Lanie laughs. "You know, you say that, but the way you're gripping that fork might suggest otherwise."

"Oh please."

Her friend lifts an eyebrow, looking completely unconvinced. "Okay, whatever you sa-"

"Okay, yes, I was just surprised that Alex wasn't… well, wasn't a man, like I had expected her to be when Castle told me her name. And I was surprised that she's-"

"Pretty?" Lanie supplies.

"Shut up." Her friend snickers into her food, leaving Beckett to continue, "I was just caught off guard, that's all. He didn't warn me, so it was a surprise, and I hate surprises. You know that."

"And you hate sharing Castle, too," Lanie mutters, making sure she can hear every word of it. "Especially since you've spent the last two weeks trying to work up the nerve to tell him that you and Josh broke up."

Her hand slips over her face. Jesus, trust Lanie to cut through it like this. "That's not-"

"It is, but since we both know it, I'll let it go. After I say this: you're being a coward, Kate Beckett, and _you_ know it. And this Alex Conrad business is just another excuse."

"Is it? Or is it just another… you remember last year, his ex-wife and publisher, and now his quote unquote mentee thing? Maybe this is just his MO?"

"Nah uh. That's you trying to find a reason not to. Now forget that, finish your meal, and go see him and tell _him_ what's on your mind."

She lowers her chin. "Or I could not," she murmurs, taking a bite of her food. "I do have more work to do, after all."

Lanie rolls her eyes. "You are waiting on everything you need right now, you do not ha-"

Kate's phone trills from her jacket pocket, interrupting Lanie's admonishments. She fishes it out and frowns at the unknown number but lifts the phone to her ear anyway.

"Beckett."

"Detective Beckett? It's Alex, is this a good time?"

She gestures to Lanie, mouths the writer's name. "Ah, n – yes. Yes, it's a good time. How are you?"

"I'm great, Detective. I just wanted to thank you again for letting me look around the precinct and throw some theories out there earlier."

Beckett licks her lips, putting her fork into the takeout carton and setting it aside. "Oh, no problem. I hope it was helpful for you."

"It was. It really was. And Rick was able to tell me a little more, but he said you would be the authority on a few things, so I figured now that I'm back in my hotel, I should call-"

"Oh, you're… you're back at your hotel."

If Conrad finds anything odd about her response, she doesn't say as much. Instead Alex steers the conversation toward a question about their typical case load and closure procedures. Kate answers everything that gets thrown at her, relaxing into the conversation after a while. This is what she's good at, being a cop. Forget everything else, the uncertainty of her own feelings about her partner, the uneasiness about his mentee; she's good at being a cop and good at talking about how to be a cop.

Almost an hour and more than a few chuckles later, Conrad thanks her. "I really appreciate this, Detective."

"Kate, please."

"Kate. Thank you for everything you told me tonight. I made so many notes and I can't wait to use them for my book."

"You're welcome, I'm just glad they'll help. Some other writer we know – who shall remain nameless, of course – tends to just make stuff up if it suits them."

Alex laughs. "He's so good at it, though."

Beckett concedes that point. "That he is."

"Have a good night, Kate."

"You, too."

Lanie looks expectant when she hangs up and puts her phone away. Sometime in the middle of Kate's phone call, Lanie had started working on reports, but she's clearly been following along too.

"Well?"

"Well what?" she asks. "You heard all of it. She was just asking me questions about procedure."

Her friend tilts her head. "And she was alone, I assume?"

Beckett shrugs. "I assume. She said she was back at her hotel, so make of that what you will."

"Did you hear anyone else?"

"Well, no."

"So, she was alone. As in _not_ with Writer Boy. Which should tell you something, don't you think?" Lanie points with her pen.

"I think it's time for me to leave," she says, taking a few more bites of her now-cold food before tossing it in the garbage. Standing, she dusts her hands over her pants. "And it's time for you to get back to work."

"Honey, I've been working."

"Yeah, yeah. Thanks for having dinner with me, Lanie." She stands, sliding into her jacket and gathering her things.

"Thanks for bringing it. Go get your man."

Her eyes lift toward the ceiling. She has never regretted telling Lanie about the breakup with Josh more than she regrets it now. Even so, spending the evening with her friend has made her feel better in general. "Good night, Lanie."

Lanie waves over her shoulder, already immersed in her paperwork.

* * *

Whatever peace she managed to find the previous night evaporates when her partner wanders into the bullpen in the morning with a cup of coffee for her in one hand and a large basket of baked goods in the other.

"Hey!"

"Hey. Baked goods?" she asks, taking the coffee from his hand and perusing the offerings in the basket when he sets it down on the edge of her desk. "What'd we do to earn this?"

Her partner shakes his head, an easy smile making its way across his face. "They're not from me this time. Alex sent them for you."

Her hand freezes mid-air, stopping just shy of the chocolate chip muffin she'd been about to choose. "O-oh. Oh. You saw Alex Conrad this morning."

Castle blinks at her about-face. "I-no. I saw them on the desk downstairs and brought them up. I haven't seen Alex since yesterday afternoon. Why?"

Beckett looks away, lifting the coffee to her lips and shaking her head. "No reason. That uh, was nice of her."

"She's nice. And she really liked you, you know. All I heard the entire time we were talking was 'Detective Beckett' this and 'Detective Beckett' that."

Yeah, she's sure.

"You made quite the impression on her, Beckett."

"So did you, Rick," she says, stressing the hard consonants of his name, earning a confused look from her partner.

"Well I'd hope so, after all, she is my mentee. Imagine being let down by your mentor; that would just be embarrassing for everyone. I have a reputation to uphold, you know."

"Yes, we wouldn't want your precious reputation to suffer for anything," she snaps.

Castle's eyes narrow. "What is that supposed to mean?"

"Nothing. Just forget it," she sighs, moving around her desk and taking a seat, making a valiant attempt at ignoring both the basket of muffins and the infuriating man who'd messengered them to her.

Thankfully, Castle lets it go, taking his seat beside her without another word. She pretends not to see him unwrap one of the offending muffins and pop it into his mouth, pretends not to see the lift of his lips and hear his hum as he eats.

Let him gloat all he wants. No matter what or whom he spends his days with, she has a case to solve, and she's not going to let that get in the way.

* * *

What she doesn't expect is for Alex Conrad to stride up to her desk the next day and offer an easy smile when she looks up.

"Alex, hey. What um, what brings you back to the precinct?"

Conrad gestures to the spot Castle typically occupies, sitting when Kate nods. "I have to be at the airport in a couple of hours, but I wanted to thank you again for everything."

Beckett nods, tilting her head. There's something else, though, something about Conrad's posture that tells her she's not sharing everything. "You're welcome, again. I hope it'll be helpful for you."

"It is. Of course, I'm going to have to change who my killer is," she says, a wry smile touching her lips, "but I know so much better now."

"Well, that's good."

Alex nods, tapping the desk. "But that's not the only reason I'm here."

And there it is.

"Until the other day, only my agent knew about me. Since we had communicated completely via email, even Rick thought Alex Conrad was some mysterious thirty-something guy he had helped make a leap into the writing world, which is what I wanted, given the number of times I'd been told by publishing houses that maybe I was better suited for… other genres. Suffice to say, he was just as surprised as you were."

Kate grimaces. She's heard similar sentiments a few dozen times in her life too. When her sights had been set on law school, throughout her time at the academy, as a beat cop, and even a couple of times in her early years as a detective. She doesn't blame Alex for playing the system.

"That said, I know how it looks that you were expecting to meet Alex and got _Alex_. It looks like Rick wasn't being honest with you, and from talking to you and your detectives, I know trust is a big thing for partners. So, I wanted to apologize."

Beckett gapes. "You – oh, no. No, you don't need to apologize for any of… that. After all, those who assume, right? I should know better, really."

Conrad laughs, shaking her head. "I know it caught you off-guard and may have strained things between you and Rick, and for that I'm sorry."

"Don't worry about me and Castle. He's done and will continue to do dumber things than this," she murmurs, lifting her lips when Alex's smile widens. "But I appreciate the fact that you thought about it at all, thank you."

"You're welcome." Alex looks around quickly, leaning in and lowering her voice. "And just to make sure we're clear, Rick is very much a professional contact, nothing more."

Kate lifts her chin, startled by the candor. "I'm not sure–"

"After all," Conrad continues, ignoring her attempt at deflection, "he didn't even know I was a girl until two days ago."

Beckett laughs. She would concede that point, but Castle isn't exactly known for being a slow mover when he's interested in someone.

"And it would be ridiculous for me to go to all this trouble to get people to respect me and accept my work on its own merits and then… with the guy who gave me the chance to get my big break. That would kind of send mixed messages."

Alex glances around again. "Not to mention there's the fact that he is absolutely _all_ about _you_."

"I-no, it's not like that. It's-" Her cheeks flame.

"Kate, even if I didn't make it a habit of being observant for my work, I have eyes. And I saw enough." She sits back. "So, just in case you were concerned… you don't have to be. Not even a little bit."

Kate stares at her, mouth agape. "I'm–"

Conrad grins, getting to her feet. "Well, I probably need to head out." She holds out a hand. "It really was great to meet you, Detective Beckett. I hope I'll get to talk to you again soon."

Beckett reaches out, shaking Conrad's hand firmly. Her cheeks still feel warm, but she'll be fine.

"You too, Alex. Let me know if Castle tells you to use anything too outlandish in your next novel so I can explain what it's like here in the real world."

The writer chuckles. "I'll be sure to do that."

Kate smiles, waving as Conrad says another goodbye and turns to leave the bullpen.

The coffee mug appears in her peripheral vision just as Conrad disappears behind the elevator doors. Turning, Beckett finds her partner waiting, a lopsided smile on his face.

"So how does it feel to be a mentor, Castle?" she asks, accepting both the mug and the peace offering it symbolizes. Maybe she had needed to hear all of that from Conrad. "Are you feeling the heavy burden of responsibility yet?"

This time when he laughs, she joins him.

"I don't feel like I did much, to be honest with you. It seems like most of what Alex got out of this visit, she got from you. I don't know whether to be jealous or impressed."

"Oh, you should definitely be impressed," she murmurs lifting her eyes to his. "Because there's no reason to be jealous."

She says it as much for herself as for him, attempting to reconcile what Conrad had said with her own feelings. She _had_ been jealous. She had been frustrated. She had wanted him all to herself. And whether he knows that or not, maybe he has felt some tinge of it as well. If not this time, because she can tell his tongue is pretty firmly lodged in his cheek here, but at another time in their history.

After a moment, her partner licks his lips and nods in acceptance.

"Okay," he says, moving to sit in his chair, getting comfortable in his place at her side.

She nods in return. "Even if Conrad did listen better than you do."

Castle feigns an offended gasp, but the delighted sparkle in his eyes tells her everything she needs to know.

They're not entirely on the same page yet, but they're getting there.

* * *

_Thank you for reading!_


End file.
